Knight shift and nuclear spin relaxation in Fe/n-GaAs heterostructures

被引：2

作者：

Christie, K. D. ^{[1
]}

Geppert, C. C. ^{[1
]}

Patel, S. J. ^{[2
]}

Hu, Q. O. ^{[3
]}

Palmstrom, C. J. ^{[2
,3
]}

Crowell, P. A. ^{[1
]}

机构：

[1] Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA

[2] Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA

[3] Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA

来源：

PHYSICAL REVIEW B | 2015年 / 92卷 / 15期

基金：

美国国家科学基金会;

关键词：

NEUTRAL-IMPURITY SCATTERING; ELECTRON-MOBILITY; GALLIUM-ARSENIDE; SEMICONDUCTORS; CONDUCTION; TRANSPORT; BAND;

D O I：

10.1103/PhysRevB.92.155204

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We investigate the dynamically polarized nuclear spin system in Fe/n-GaAs heterostructures using the response of the electron-spin system to nuclear magnetic resonance (NMR) in lateral spin-valve devices. The hyperfine interaction is known to act more strongly on donor-bound electron states than on those in the conduction band. We provide a quantitative model of the temperature dependence of the occupation of donor sites. With this model we calculate the ratios of the hyperfine and quadrupolar nuclear relaxation rates of each isotope. For all temperatures measured, quadrupolar relaxation limits the spatial extent of nuclear spin polarization to within a Bohr radius of the donor sites and is directly responsible for the isotope dependence of the measured NMR signal amplitude. The hyperfine interaction is also responsible for the 2 kHz Knight shift of the nuclear resonance frequency that is measured as a function of the electron-spin accumulation. The Knight shift is shown to provide a measurement of the electron-spin polarization that agrees qualitatively with standard spin transport measurements.

引用

页数：8

共 42 条

[1]

Abragam A., 1983, Principles of Nuclear Magnetism

[2] Spin injection and relaxation in ferromagnet-semiconductor heterostructures [J].

Adelmann, C ;

Lou, X ;

Strand, J ;

Palmstrom, CJ ;

Crowell, PA .

PHYSICAL REVIEW B, 2005, 71 (12)

[3] Mixed conduction in doped semiconductor structures related to quasi-metallic conduction in the impurity band [J].

Agrinskaya, N. V. ;

Kozub, V. I. ;

Poloskin, D. S. .

SEMICONDUCTORS, 2010, 44 (04) :472-477

[4]

[Anonymous], 2000, Handb Chem Phys

[5] Hyperfine interactions and spin transport in ferromagnet-semiconductor heterostructures [J].

Chan, M. K. ;

Hu, Q. O. ;

Zhang, J. ;

Kondo, T. ;

Palmstrom, C. J. ;

Crowell, P. A. .

PHYSICAL REVIEW B, 2009, 80 (16)

[6] COMPENSATION DEPENDENCE OF IMPURITY CONDUCTION IN ANTIMONY-DOPED GERMANIUM [J].

DAVIS, EA ;

COMPTON, WD .

PHYSICAL REVIEW, 1965, 140 (6A) :2183-&

[7]

DYAKONOV MI, 1973, ZH EKSP TEOR FIZ+, V65, P362

[8] Low-temperature spin relaxation in n-type GaAs -: art. no. 245204 [J].

Dzhioev, RI ;

Kavokin, KV ;

Korenev, VL ;

Lazarev, MV ;

Meltser, BY ;

Stepanova, MN ;

Zakharchenya, BP ;

Gammon, D ;

Katzer, DS .

PHYSICAL REVIEW B, 2002, 66 (24) :1-7

[9] NEUTRAL IMPURITY SCATTERING IN SEMICONDUCTORS [J].

ERGINSOY, C .

PHYSICAL REVIEW, 1950, 79 (06) :1013-1014

[10] ELECTRICAL PROPERTIES OF GERMANIUM SEMICONDUCTORS AT LOW TEMPERATURES [J].

FRITZSCHE, H .

PHYSICAL REVIEW, 1955, 99 (02) :406-419

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